Answer:
A, C
Step-by-step explanation:
Actually, those questions require us to develop those equations to derive into trigonometrical equations so that we can unveil them or not. Doing it only two alternatives, the other ones will not result in Trigonometrical Identities.
Examining
A) True
Double angle 
B) False,
No further development towards a Trig Identity
C) True
Double Angle Sine Formula 
D) False No further development towards a Trig Identity
![[sin(x)-cos(x)]^{2} =1+sin(2x)\\ sin^{2} (x)-2sin(x)cos(x)+cos^{2}x=1+2sinxcosx\\ \\sin^{2} (x)+cos^{2}x=1+4sin(x)cos(x)](https://tex.z-dn.net/?f=%5Bsin%28x%29-cos%28x%29%5D%5E%7B2%7D%20%3D1%2Bsin%282x%29%5C%5C%20sin%5E%7B2%7D%20%28x%29-2sin%28x%29cos%28x%29%2Bcos%5E%7B2%7Dx%3D1%2B2sinxcosx%5C%5C%20%5C%5Csin%5E%7B2%7D%20%28x%29%2Bcos%5E%7B2%7Dx%3D1%2B4sin%28x%29cos%28x%29)
Answer:
Please see attached picture for full solution.
Answer:
Step-by-step explanation:
you want to divide 36 by 8 because you have 36 people and the recipie only makes it for 8.
You know that you will need to make the recipe 4.5 times.
So, multiply all the ingredient numbers by 4.5
2 x 4.5 = 9 quarts of water
3 x 4.5 = 13.5 sticks of cinnamon
1 x 4.5 = 4.5 tablespoons of coffee
I think i know this one. it's 3,281.
(cos(x) + cos(y))^2 + (sin(x) - sin(y))^2 Remove the brackets
cos^2(x) + cos^2(y) + 2cos(x)*cos(y) + sin^2(x) - 2(sin(x)*sin(y) + sin^2(y) Combine these two in bold to make 1 because sin^2(x) + cos^2(x) = 1
1 + cos^2(y) + 2cos(x)*cos(y) - 2*sin(x)*cos(y) + sin^2(y)
These two in bold also make 1
2 + 2cos(x)*cos(y) - 2*sin(X)*sin(y) Bring out a common factor of 2
2 +2(cos(x)*cos(y) - sin(x)*sin(y) )
but cos(x+y ) = cos(x)*cos(y) - sin(x)*sin(y)
2 + 2* cos(x + y) is your final answer.
